The performance and accuracy of flow metering systems used for transfer of large quantities of fluids, such as hydrocarbon quantities, is typically checked by periodic verification of the measuring equipment and audits of the metering procedures, data and records.
The correction of measured quantities is often an elaborate activity based on labor-intensive data analysis and most often incomplete information. Assumptions have to be made about the actual occurrence, magnitude and duration of any issue that may have led to a measurement error. Measurement auditing becomes more and more complicated because of the increasing amount of data generated by electronic flow meters, transmitters and process analyzers.
API Manual of Petroleum Measurement Standards (MPMS)—Chapter 21 Flow Measurement Using Electronic Metering Systems Part 1: Electronic Gas Measurement, 1st Edition, American Petroleum Institute, 1 Aug. 1993, 38 pages, and API Manual of Petroleum Measurement Standards (MPMS)—Chapter 21 Flow Measurement Using Electronic Metering Systems Part 2: Electronic Liquid Measurement, 1st Edition, American Petroleum Institute, 1 Jun. 1998, 60 pages, provides guidelines for performing diagnostics and discrepancy checks by a metering control system. These checks may assist metering engineers to detect or prevent measurement failures. API MPMS further discloses data sampling and averaging techniques that may simplify the correction of measurement errors regarding the transported quantity of fluid.